One of the snappiest sitcom theme songs in the history of the boob tube was penned by Jeff Barry. "One Day at a Time," with its never-say-die lyrics, is an ode to optimism in times of crisis, flat tires, paper cuts, torrential downpours - or, in this case, divorce and single parenthood. The series of the same name aired during the 70's and starred Bonnie Franklin, Pat Harrington Jr., Valerie Berinelli, and Mackenzie Phillips.
Check out this interesting blog post on DrinkatWork.com which provides commentary and lyrics. The post includes links for listening to the "One Day at a Time" theme and for viewing the opening credits.